Hatfield Police Station And Magistrates Court (495456784, v1)
This is duplication and outline has self intersection, (not to OSM best practice) so removed.

Hello, I removed the sidewalk tags, they are used on a footpath beside a road but separated from the road usually by a kerb.
Removed several duplicated sections of path and tidied up some paths, circularised a couple of paths. Regards Bernard

Expand abbreviation of church name. Adjust building outlines.

Adjust areas, remove self intersecting section, remove duplicated areas from school.

Hi, you've placed the node (1689605515 105 Fenchurch St) on the party wall between two buildings.

I set post code to OSM standard.

Forgot to say I can see what you are trying to do and could make those changes if you wish, though I'm sure you'd like to do it yourself.

Hello, the problems with Dancers Hill Road are the same as the Great North Road. What has happened is that the path has been dragged to a new position without it being disconnected from the two roads. This inadvertently pulls the two roads out of shape by the same amount. The path has then been amended to the new route, the south end being adjusted more than the north. Thus the south end is more out of correct position than the north, (you can see the difference more on the south road than the north road). I can replicate this problem/behavior by temporarily reverting your changes then dragging the path in the manner described above. Thus I'm sure something like this has happened.
I have made one change only, to revert your changeset to the original state, the roads north and south as well as the woods area are back as they were.

To move this path without affecting anything else first disconnect it from other ways (just to highlight/select it and move it also moves the points where it is joined to other ways). Then move the endpoints (nodes) to the new position and join the endpoints to the road. Then proceed to adjust the center section of the way.
You can disconnect the path, highlight/select it and move the whole thing at once but it won't fit in so the ends and center still have to be adjusted then ends joined to roads.

If I can help in any way please just ask. Regards Bernard.

Hello and Welcome to OpenStreetMap.
Your moving of the footpath has also dragged the roads at each end out of place. May I suggest reverting the changes and starting again. I can revert everything back as it was for you if you wish. The two roads need to be corrected as now routing is messed up. Regards Bernard.

Hi, can you give more details about the park the name perhaps. Because that area contains much that does not look like a park. Thanks.

Hi and welcome to OpenStreetMap.
You drew the park area again rather than updating/adjusting the existing mapped area. I have removed the duplication and tagged the area as park, leaving existing tags and history in situ.
Regards Bernard

Hello and Welcome to OpenStreetMap.
Your POI guest house is placed in the roadway. As such and without an address, name or other contact info it is of little or no use to anyone. Could you please rectify this if not the POI will be removed in due course.
Regards Bernard

Hello your POI appears in the middle of a street far away from the stated address. If this is a mistake then please be advised that the POI has been removed so you can try again.In which case help is offered if you need it, just ask.
If however this is just crude advertising (which it looks like) then it hasn't worked, please go away.
Regards Bernard

Hello you inadvertently added a highway=footway tag to the outline of part of a residential area (making it the longest footway I've seen). I have now removed the footway tag.
Regards Bernard

If your changeset statement is correct then you've placed this POI in the wrong position. That hotel is south of here. Regards Bernard

Hello and welcome to OpenStreetMap.
I can find no reference to a government office of this name and the area is residential. Could you please give more information, address and point to the actual building. Thanks.

Hello and welcome to OpenStreetMap.
Your leisure centre building outline is lacking in detail compared with the background image. It is also a duplication, thus I have removed the duplicate taking care to transfer your address tags onto the original building.
Regards Bernard.

Reverted your change. Byron's Pool is a local nature reserve, please see the tagged webpage. There are numerous County Council references to the nature reserve, none state as being a park.

Hi, as you can see from the link the oneway tag is to be avoided unless it is needed to avoid other errors. It would actually do no harm if left. But best practice though would be to remove the oneway=no tags thus avoiding unnecessary bloat on the database.
If you need any help please just ask. Regards Bernard

Hi and Welcome to OpenStreetMap.
Regarding the POI for a park you added, a POI is not really good for an area so I took the liberty of adding the area outline as best I could from Bing image. Secondly it's a private garden rather than a park, tags adjusted to suit garden. Regards